Transcript lecture3-joints

Prof. Saeed Abuel Makarem
Dr.Sanaa Alshaarawy : 2013
OBJECTIVES
By the end of the lecture, students should
be able to:
 Define the term “Joint”.
 Describe the classification of the 3 types of
joints & give an example of each.
 Describe the characteristics of synovial joints.
 Describe the classification of synovial joints &
give an example of each.
 List factors maintaining stability of joints.
 Recite “Hilton’s law” for nerve supply of joints.
DEFINITION
• What is a joint?
• It is the site
where two or
more bones
meet together.
CLASSIFICATION
Joints are classified
according to the
tissues that lie
between the bones
into:
1. Fibrous.
2. Cartilaginous.
3. Synovial.
FIBROUS JOINTS
• The articulating surfaces
are joined by fibrous
connective tissue, where
No or very mild movement
1. Skull sutures:
Temporary (as it ossify
later).
2.
3.
Inferior tibiofibular
joints (syndesmosis):
minimal movement,
permanent joints.
Gomphosis: dental
alveolar joints.
CARTILAGINOUS JOINTS
• The Two bones are joined by
cartilage.
• It is of 2 types:
 Primary Cartilaginous
(synchondrosis):
• The bones are united by a
plate or a bar of hyaline
cartilage.
• No movement, temporary
joints (ossify later), example:
1. Between the Epiphysis and
the Diaphysis of a growing
bone.
2. Between the First Rib and the
Sternum (1st sternocostal
joint).
Primary Cartilaginous
CARTILAGINOUS JOINTS
 Secondary Cartilaginous
• The bones are united by a
plate of fibrocartilage.
• Their articulating surfaces are
covered by a thin plate of
hyaline cartilage.
• Little movement, permanent
joints.
• The are called Midline joints.
1. Joints between the Vertebral
Bodies (intervertebral discs).
2. Symphysis Pubis.
SYNOVIAL JOINTS
 Characteristic features:
• Freely movable joints.
• The 2 bones are joined by
a fibrous capsule, which
is attached to the margins
of articular surfaces &
enclosing the joint.
• The articular surfaces are
covered by a thin layer of
hyaline cartilage
(articular cartilage).
• A joint cavity enclosed
within the capsule.
Capsule
SYNOVIAL JOINTS
• Synovial membrane :
a thin vascular
membrane lining the
inner surface of the
capsule.
• Synovial fluid : a
lubricating fluid
produced by the
synovial membrane in
the joint cavity.
• The fluid minimizes
the friction between
the articular surfaces.
CLASSIFICATION OF SYNOVIAL JOINTS
Synovial joints can be
classified according to:
•The arrangement of the
articular surfaces.
•The range of movement that
are possible
 So according to the range
of movement synovial
joints are classified into:
• Plane synovial joints.
• Axial synovial joints.
PLANE SYNOVIAL JOINTS
• The articulating
surfaces are flat
and the bones
slide on one
another, producing
a gliding
movement.
example;
1. Intercarpal
Joints.
2. Sternoclavicular
3. Acromioclavicular
joints.
AXIAL SYNOVIAL JOINTS
 Movements occur
along axes:
1. Transverse: flexion &
extension occur.
2. Longitudinal: rotation
occurs.
3. Antero-posterior:
abduction &
adduction occur.
 Axial joints are
divided into:
1. Uniaxial.
2. Biaxial.
3. Multi-axial (polyaxial).
UNIAXIAL SYNOVIAL JOINTS
Hinge joints:
• Axis: transverse.
• Movements: flexion
& extension.
• Example: elbow and
ankle joints.
Pivot:
• Axis: longitudinal.
• Movements:
rotation.
• Example: radio-ulnar
joints
BIAXIAL SYNOVIAL JOINTS
Ellipsoid joints:
• An elliptical convex
fits into an elliptical
concave articular
surface.
• Axes: Transverse &
antero-posterior.
• Movements: Flexion
& extension +
abduction &
adduction but
rotation is impossible.
• Example: Wrist joint.
BIAXIAL SYNOVIAL JOINTS
Saddle joints:
• The articular surfaces are
reciprocally
concavoconvex.
• They resemble a saddle
on a horse’s back.
• Movement: As ellipsoid
joints (Flexion &
extension + abduction &
adduction) + a small
range of rotation .
• Example:
Carpometacarpal joint of
the thumb.
POLYAXIAL SYNOVIAL JOINTS
Ball-and-socket joints:
• A ball –shaped head of a
bone fits into a socket-like
concavity of another.
• Movements: Flexion &
extension + abduction &
adduction) + rotation
along a separate
axis.
• Examples:
1. Shoulder joint.
2. Hip Joint.
STABILITY OF SYNOVIAL JOINTS
1-The shape of articular
surfaces:
• The ball and socket
shape of the Hip joint
is a good examples of
the importance of bone
shape to maintain joint
stability.
• The shape of the bones
forming the Knee joint
has nothing to do for
stability.
STABILITY OF SYNOVIAL JOINTS
2-Strength of the
ligaments:
• They prevent
excessive
movement in a
joint.
• Example:
cruciate
ligaments of
the knee joint.
STABILITY OF SYNOVIAL JOINTS
3- Tone of the surrounding
muscles:
• In most joints, it is the
major factor controlling
stability.
• The short muscles around
the shoulder joint keeps
the head of the humerus
in the shallow glenoid
cavity.
NERVE SUPPLY OF JOINTS
• The capsule and ligaments receive an
abundant sensory nerve supply.
• Hilton’s law:
“A sensory nerve supplying a joint also supplies
the muscles moving that joint and the skin
overlying the insertions of these muscles.”
GOOD LUCK
SUMMARY
Joint is the site where two or more bones
come together, whether movement occurs or
not between them.
Joints are classified according to the tissues
that lie between the bones into 3 types:
fibrous, cartilaginous & synovial.
Synovial joints are freely movable &
characterized by the presence of : fibrous
capsule, articular cartilage, synovial
membrane & joint cavity containing synovial
fluid.
SUMMARY
Synovial joints are classified according to the
range of movement into: plane and axial.
Axial are divided according to the number of axes
of movements into: uniaxial, biaxial & polyaxial
or multiaxial.
Stability of synovial joints depends on: shape of
articular surfaces, ligaments & muscle tone.
Joints have same nerve supply as muscles moving
them.
QUESTION
Which of the following is a hinge synovial
joint?
1. Shoulder.
2. Elbow.
3. Sternoclavicular.
4. Symphysis pubis.
QUESTION
Which of the following is a cartilaginous joint?
1. Hip.
2. Elbow.
3. Sternoclavicular.
4. Symphysis pubis.
Which of the following is a pivot synovial joint?
1. Shoulder.
2. Elbow.
3. Sternoclavicular.
4. Radioulnar.